2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/70185We give a complete list of formal invariants for a large class of formal differential 1-forms $\w \in \Bbb C [[ x, y]]dx + \Bbb C [[ x, y]]dy$. \indent A $\hat{SL}$-equisingular deformation is an equireducible deformation which leaves invariant both the local formal types and the holonomy representation of the components of the exceptional divisor. We characterize the 1-forms with finite formal type (t.f.f), i.e. those which admit a semi-universal $\hat{SL}$-equisingular deformation, and we give an explicit combinatorial criterion of finiteness. \indent The set of 1-forms with finite formal type contains a dense open set (in the sense of Krull's topology)in the set of 1-forms of the second kind.89 pages, frenchDynamical SystemsComplex Variables32A10, 32A20, 32B10,34C20, 34C35, 58F23, 32G34, 32S15, 32S30, 32S45, 32S65text